The present invention relates to the field of the graphical representation of networks, and more precisely to a process for depicting, within such a representation, a set of paths which are available in order to undertake a routing between two nodes of the network.
The networks represented may be of very diverse kinds. The example more particularly envisaged by the Applicant concerns telecommunication networks. Other examples would be energy transport or fluid distribution networks, etc.
In a natural way, the graphical representation of such a network comprises symbols designating nodes of the network (for example, switches in the case of a telecommunication network), which are connected together by arcs designating elementary links existing between nodes of the network (for example, bundles of cables, optical or radio-relay fibers, etc.).
When the network comprises many nodes and many links, this very frequently being the case, its representation becomes complex and difficult to read. In particular, the depicting of the paths available to transport a stream (of information, of signals, of energy, of fluid etc.) from one node to another is a problem which is difficult to solve in a clear and unambiguous manner.
It is just such a set of paths available for transporting a stream from a first node to a second node of the network which it is proposed to depict according to the invention. This set of paths obeys the following topological rules:
each path of the set includes, between the first node and the second node, an elementary link or a succession of elementary links each having a respective departure node and a respective arrival node, PA1 the first node constitutes the departure node of an elementary link of each path, PA1 the second node constitutes the arrival node of an elementary link of each path, and PA1 each arrival node of an elementary link of a path of the set other than said second node constitutes the departure node of another elementary link of said path.
Moreover, it may be necessary to display certain routing rules on the depiction of the set of paths, these rules applying within this set. Among these rules may be mentioned load sharing as well as the modes of behavior to be adopted in the event of an overflow on a link. FIG. 1 illustrates a conventional way of representing a set of paths between a node A and a node B together with such rules. In this example, the normal route between nodes A and B consists in taking the direct link AB. However, in the event of an overflow of capacity on this direct link, the streams to be routed from node A to node B may take either the path AT.sub.1 B, or the path AT.sub.2 B. The sharing of the overflow load between the elementary links AT.sub.1 and AT.sub.2 is represented by the ellipse e drawn around the arcs designating these two elementary links, and the arrow f emanating from the arc AB is an overflow indicator which makes it possible to depict the appropriate behavior in the event of an overflow on the link AB.
The depiction technique illustrated by FIG. 1 has several practical limitations. For certain arrangements of the nodes within the representation, the route is incomprehensible. For example, in FIG. 1, if node B is placed between nodes T.sub.1 and T.sub.2, the representation of the route is no longer comprehensible. However, the option of modifying the position of the nodes in order to avoid such ambiguities is not always available: such is the case, in particular, when the position of the nodes reflects the geography of the sites of the network. Furthermore, this depiction technique does not bind a choice of route to the node on exit from which this choice is made, but to the arcs representing the links concerned. This makes it difficult to track the paths taken by the stream from end to end. Another limitation is that it is not possible to display clearly the fact that a choice of route on exiting a node can be conditioned by the link via which the stream has reached this node.
An object of the present invention is to improve the techniques for depicting paths within graphical representations of networks by simultaneously endowing them with greater visibility and larger richness of representation.